1. Field of the Invention
The present invention relates to valves for use in heated and pressurized fluid flow, such as the conveyancing of steam. In particular, the present invention relates to a self-contained, thermostatic temperature and pressure operated pinch valve in which the path of fluid flow through said valve may be automatically controlled by the temperature and pressure of a flow material, said pinch valve comprising:
(a) connection means adapted to incorporate said pinch valve within the path of said flow material; PA1 (b) a flow transport path for fluid flow through said valve, comprising: PA1 (c) a closure chamber within said valve and at least partly surrounding said flow adjustment means, said closure chamber being further provided with a closure means in direct operative communication with said flow adjustment means, and in operative communication with said sensing means; PA1 (a) connection means adapted to incorporate said pinch valve within the path of said flow material; PA1 (b) a flow transport path for fluid flow through said valve, comprising: PA1 (c) a closure chamber within said valve and at least partly surrounding said flow adjustment means, said closure chamber being further provided with a closure means in direct operative communication with said flow adjustment means, and in operative communication with said sensing means;
i) an inlet for the transport of flow material into said valve; PA2 ii) a flow adjustment means comprising a flexible tube surrounding and defining at least a portion of said flow transport path, said flow adjustment means adapted to alternatively decrease the fluid flow in that portion of said flow transport path defined by said flow adjustment means upon an increase of pressure on a surface of the flow adjustment means or increase the fluid flow in the path upon a decrease of pressure on a surface of the flow adjustment means; and, PA2 iii) a flow measurement chamber within said flow transport path in direct pressure and temperature communication with said flow material, said flow measurement chamber being further provided with sensing means in direct pressure and temperature communication with the flow material; and, PA2 iv) an outlet for the transport of flow material from said valve; and, PA2 i) an inlet for the transport of flow material into said valve; PA2 ii) a flow adjustment means comprising a flexible tube surrounding and defining at least a portion of said flow transport path, said flow adjustment means adapted to alternatively decrease the fluid flow in that portion of said flow transport path defined by said flow adjustment means upon an increase of pressure on a surface of the flow adjustment means or increase the fluid flow in the path upon a decrease of pressure on a surface of the flow adjustment means; and, PA2 iii) a flow measurement chamber within said flow transport path in direct pressure and temperature communication with said flow material, said flow measurement chamber being further provided with sensing means in direct pressure and temperature communication with the flow material; and, PA2 iv) an outlet for the transport of flow material from said valve; and,
wherein, said closure means is adapted to provide operative pressure upon said flow adjustment means in response to changes in the temperature and pressure of the flow material as determined by said sensing means.
2. Description of Related Art
Various forms of valves and steam traps are known which employ a plug-within-a-seat to interrupt the flow of steam. Where the steam is pressurized, however, the valve actuation means must be sensitive to both temperature and pressure, and not just temperature alone. In order to prevent the passage of live steam through the valve, without backing up a column of condensate, such a valve must follow the steam curve, i.e., the liquid-vapor transition of the fluid as a function of both its temperature and pressure. A number of activation means are known which are said to be sensitive to both temperature and pressure, i.e., they follow the steam curve. These include bimetallic discs, float, open bucket or inverted bucket, and bellows mechanisms.
Plug-within-a-seat valves and steam traps, however, are subject to failure in systems containing any kind of dirt or grit, wherein a small particle of dirt can prevent the plug from seating correctly and cause the valve to malfunction.
An alternative to plug-within-a-seat construction, which does not suffer from this kind of failure, is the pinch valve. In such construction, the steam flows through a conduit, at least a portion of which is elastomeric, and the flow can be interrupted by squeezing the elastomeric walls together (pinch). While this type of construction has been employed in constructions in which a temperature sensitive fluid expands to close off the elastomeric passageway, this known construction is sensitive only to temperature, not the combination of temperature and pressure, and cannot be employed in applications which require the valve to follow the steam curve.
Applicant is not aware of the application of a pinch valve construction in a valve or steam trap design in which the activation mechanism is sensitive to temperature and pressure, such as the activation methodologies enumerated above.
Certainly, one of the most pertinent references to the present invention is U.S. Pat. No. 4,454,983 to Tarvis, entitled TEMPERATURE CONTROLLED VALVE. This reference shows a control valve used as a steam trap with a flexible flow tube surrounded by a chamber filled with a fluid having a high co-efficient of thermal expansion in thermal contact with the flow. Changes in temperature of the flow will cause changes in the fluid volume, constricting the flexible flow tube. While the device of this reference is sensitive to the temperature of the flow, it is relatively isolated from the pressure of the flow, and so does not follow the temperature-pressure curve for the flow. Cited in the prosecution of the Tarvis patent were U.S. Pat. Nos. 566,977 to Frohlich; 596,581 to Edson; 875,320 to Burnet; 1,048,508 to Dunham; 1,120,707 to Frohlich; 1,198,918 to Holmberg; 2,095,506 to Leutwiler; 2,590,215 to Sausa; 2,804,773 to Domingo and Peragallo; 2,884,866 to Patterson; 2,902,222 to Noakes; 3,017,903 Steffens; 3,022,670 to Suttiffe; 3,145,967 to Gardner; 3,353,560 to McCulloch; 3,514,034 to Cushman; 3,687,365 to Laessig; and, 4,248,376 to Foller, as well as United Kingdom Patent 16,545 of 1903.
Of possible relevance are U.S. Pat. Nos. 2,842,331 to Anderson; 3,901,438 to Christiansson; 4,114,640 to Forman; and 4,569,502 to Elliott.
U.S. Pat. No. 2,842,331 to Anderson is entitled PINCH-OFF VALVE. This reference shows a valve used to mechanically pinch off a fluid flow.
U.S. Pat. No. 3,901,438 to Christiansson is entitled THERMOSTAT-REGULATED RADIATOR VALVE FOR SINGLE OR DOUBLE CONDUIT CENTRAL HEATING SYSTEMS. This reference shows a radiator valve regulated by a thermostat. Working fluid is provided to a radiator through a flexible conduit which can be pinched closed by a bimetalic cylinder in response to the temperature of a thermodynamically-spent return fluid flow. The device is, as reported, sensitive only to temperature, and the bimetallic element is in temperature contact only with the spent fluid flow. As such, it would be unsuitable in applications requiring operation activated by a combination of temperature and pressure. That is, it would not be responsive to the steam curve.
Secondly, the device has two distinct flow paths: one for flow of working fluid into a working environment; and another, separate path for the return flow of thermodynamically-spent fluid from the working environment, subsequent to its thermodynamic function. It is the primary purpose of the device of the Christiansson reference that the flow of working fluid in the intake path is controlled by the temperature, and the temperature only, of the spent fluid in the return path.
U.S. Pat. No. 4,114,640 to Forman is entitled DRAIN VALVE. This reference shows a two-part device which may be attached to a flexible tube, such as the outlet tube of a medical solution drainage bag employed in hospital and health care applications. The two part clip may be squeezed together to interrupt fluid flow and protect the open end of the tubing from contamination. The device is intended for manual operation, with no suggestion of any control by the temperature or pressure of the fluid.
U.S. Pat. No. 4,569,502 to Elliot is entitled PINCH VALVE. This reference shows a manually actuated pinch valve having a flexible valve body. The device is intended for manual operation, with no suggestion of any control by the temperature or pressure of the fluid.
U.S. Pat. No. 3,701,513 to Carter is entitled FUEL FEEDING APPARATUS. This reference shows a device for intermixing liquid fuel, air, and a measured proportion of water for delivery to an internal combustion engine. The liquid fuel is supplied by way of a compressible elastomeric tube.
U.S. Pat. No. 3,947,258 to Decker is entitled VAPOR STRIPPING AND RECOVERY METHOD AND APPARATUS. This reference shows a method and apparatus for removing vapors from an air-vapor mixture.
U.S. Pat. No. 4,586,873 to Lepretre, Balzano, Caillault is entitled MIXER-EJECTOR WITH JET EFFECT AND VARIABLE CROSS-SECTION. This reference shows a mixer-ejector with jet effect incorporates inductor nozzles opening into a venturi profile conduit having in succession a highly convergent suction sleeve, a coupling wall and a diffuser. The coupling wall is a variable-profile venturi part, consisting of a hollow sleeve made of distortable elastic material in a casing with leaktight sealing and incorporates means for introducing a fluid into the enclosure formed by the sleeve and the casing.
U.S. Pat. No. 4,790,344 to Chauvier and Woodman is entitled FLUID FLOW REGULATOR. This reference shows a submersible cleaner in which the inlet may be regulated by pressurizing a chamber surrounding a collapsible conduit.
U.S. Pat. No. 4,841,739 to Wallner is entitled AUTOMOTIVE AIR-CONDITIONING SYSTEM AND APPARATUS. This reference shows an auto air-conditioner, with a refrigerant circuit with a low-pressure portion and a high-pressure portion. A pressure-release valve with a blow-off outlet is provided between the compressor and the condenser in the high-pressure portion.
U.S. Pat. Nos. 4,877,053, 4,895,341, and 4,899,783 are all based upon the same original U.S. patent application to Yusko, Brown, Kalain, and Williams are each entitled PINCH VALVE. These references shows some rather sophisticated pinch valves intended for use in biotechnological environments. These pinch valves are said to be useful because if the valving mechanism does not come into contact with the material conveyed, then the valve does not become contaminated and require extensive sterilization and cleaning. The pinch valves of these references are intended to pinch off elastomeric conduits under the control of an operator.
U.S. Pat. No. 5,107,883 to Shaw is entitled PINCH VALVE CONTROL SYSTEM FOR WATER LINE ISOLATION AND METHOD. This reference shows a pinch valve control system for regulating the flow of water through the water distribution network of a building. Remote-controlled, fluid-operated pinch valves are spaced at various locations throughout the water distribution network of the building and may be selectively operated from a remote station to stop the flow of water in any pipe throughout the building's water distribution network. The use of pinch valves permits water flow to be increased or decreased gradually and reduces or eliminates water hammer. The pinch valve is operated by compressed fluid which enters the sleeve around the pinch valve to stop the flow of water in the pipe. To resume the water flow, the fluid in the pinch valve is released.